Stonewall prevents expression of ectopic genes in the ovary and accumulates at insulator elements in D. melanogaster.
Stonewall prevents expression of ectopic genes in the ovary and accumulates at insulator elements in D. melanogaster.
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DOI：
10.1371/journal.pgen.1010110
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发表时间：
2022-03
期刊：
影响因子：
4.5
通讯作者：
Barbash DA
中科院分区：
文献类型：
--
作者：
Zinshteyn D;Barbash DA
生殖干细胞（GSC）是动物一生中生殖系的祖细胞。在果蝇中，这些细胞存在于维持（自我更新）和分化（不对称分裂产生不同于 GSC 的子细胞）所需的细胞生态位中。干细胞-子细胞转变受到许多过程的严格调控，包括基因组稳定性所需的一系列蛋白质。生殖干细胞维持因子 Stonewall (Stwl) 与异染色质相关，但其分子功能知之甚少。我们对 stwl 突变体卵巢进行了 RNA 测序，发现许多转座子家族显着去抑制，但异染色质基因没有显着去抑制。我们还发现了多类基因的不适当表达。最突出的是富含睾丸的基因，包括雄性种系性别决定开关 Phf7、分化因子 bgcn 和 2 号染色体上的大型睾丸特异性基因簇，所有这些基因在 stwl 突变卵巢中均上调或异位表达。令人惊讶的是，我们还发现体细胞 S2 细胞中 stwl 的 RNAi 敲低导致这些睾丸基因的异位表达。在 S2 细胞中使用并行 ChIP-Seq 和 RNA-Seq 实验，我们发现 Stwl 定位于转录起始位点的上游和异染色质序列，包括与端粒相关的重复序列。 Stwl 在 bgcn 处也富集，表明它直接调节这种重要的分化因子。最后，我们鉴定了与已知绝缘体结合蛋白共享的 Stwl 结合基序。我们认为，Stwl 通过结合绝缘体和建立染色质边界来影响基因调控，包括抑制雌性种系中的雄性转录本。干细胞的定义是其不对称分裂的能力，从而产生分化细胞和干细胞子代。在果蝇中，精子和卵子的产生始于生殖干细胞（GSC）。 GSC 的分化或自我更新能力受到多种因素的严格调控。其中一些是转录因子，它们负责激活或抑制其他基因，以促进一种状态有利于另一种状态。 Stonewall 是 GSC 自我更新所需的一种卵巢核蛋白，但其分子功能尚不清楚。在这里，我们表明石墙负责阻止果蝇卵巢中“雄性”分子编程的激活。当卵巢中不存在 Stonewall 时，卵子产生就会终止，睾丸特异性基因就会高度表达，其中包括 Phf7 的雄性转录物，它会在雌性生殖细胞中诱导雄性性别认同。我们还表明，石墙很可能定位于基因组绝缘体，这些绝缘体是基因组中保护基因免受附近调节因子影响的区域。我们的研究结果表明，Stonewall 有助于组织卵巢生殖细胞中的基因组并阻止男性基因的表达。
Germline stem cells (GSCs) are the progenitor cells of the germline for the lifetime of an animal. In Drosophila, these cells reside in a cellular niche that is required for both their maintenance (self-renewal) and differentiation (asymmetric division resulting in a daughter cell that differs from the GSC). The stem cell—daughter cell transition is tightly regulated by a number of processes, including an array of proteins required for genome stability. The germline stem-cell maintenance factor Stonewall (Stwl) associates with heterochromatin, but its molecular function is poorly understood. We performed RNA-Seq on stwl mutant ovaries and found significant derepression of many transposon families but not heterochromatic genes. We also discovered inappropriate expression of multiple classes of genes. Most prominent are testis-enriched genes, including the male germline sex-determination switch Phf7, the differentiation factor bgcn, and a large testis-specific gene cluster on chromosome 2, all of which are upregulated or ectopically expressed in stwl mutant ovaries. Surprisingly, we also found that RNAi knockdown of stwl in somatic S2 cells results in ectopic expression of these testis genes. Using parallel ChIP-Seq and RNA-Seq experiments in S2 cells, we discovered that Stwl localizes upstream of transcription start sites and at heterochromatic sequences including repetitive sequences associated with telomeres. Stwl is also enriched at bgcn, suggesting that it directly regulates this essential differentiation factor. Finally, we identify Stwl binding motifs that are shared with known insulator binding proteins. We propose that Stwl affects gene regulation, including repression of male transcripts in the female germline, by binding insulators and establishing chromatin boundaries. Stem cells are defined by their ability to divide asymmetrically, resulting in a differentiated cell and a stem cell daughter. In fruit flies, sperm and egg production begins with germline stem cells (GSCs). The ability of a GSC to differentiate or self-renew is tightly regulated by a myriad of factors. Some of these are transcription factors, which are responsible for activating or suppressing other genes to promote one state in favor of another. Stonewall is an ovarian nuclear protein required for GSC self-renewal, whose molecular function is poorly understood. Here we show that Stonewall is responsible for preventing the activation of “male” molecular programming in the fruit fly ovary. When Stonewall is absent from the ovary, egg production is terminated and testis-specific genes become highly expressed, including the male transcript of Phf7, which induces male sexual identity in female germ cells. We also show that Stonewall is likely localizing to genomic insulators, which are regions of the genome that shield genes from nearby regulators. Our findings suggest that Stonewall helps to organize the genome in ovarian germ cells and prevent expression of male genes.
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DOI：
10.1093/bioinformatics/btu638
发表时间：
2015-01-15
期刊：
Bioinformatics (Oxford, England)
影响因子：
--
作者：
Anders S;Pyl PT;Huber W
通讯作者：
Huber W
影响因子：
48
作者：
Langmead, Ben;Salzberg, Steven L.
通讯作者：
Salzberg, Steven L.
影响因子：
23.9
作者：
Insco, Megan L.;Bailey, Alexis S.;Kim, Jongmin;Olivares, Gonzalo H.;Wapinski, Orly L.;Tam, Cheuk Ho;Fuller, Margaret T.
通讯作者：
Fuller, Margaret T.
影响因子：
64.8
作者：
通讯作者：
--
DOI：
10.1534/g3.114.015875
发表时间：
2015-02-09
期刊：
G3 (Bethesda, Md.)
影响因子：
--
作者：
Flores HA;DuMont VL;Fatoo A;Hubbard D;Hijji M;Barbash DA;Aquadro CF
通讯作者：
Aquadro CF